It is well known to provide a refrigeration system including a refrigeration device such as a refrigerated case, refrigerator, freezer, etc. for use in commercial, institutional and industrial applications involving the storage and/or display of objects, products and materials. For example, it is known to provide a refrigeration system with one or more refrigerated cases for display and storage of frozen or refrigerated foods in a supermarket to maintain the foods at a suitable temperature (e.g. 32 to 35 deg F.). Such systems may include a primary refrigerant loop and a secondary cooling loop that interface with one another through a heat exchanger so that a primary refrigerant cools or chills a liquid coolant that is circulated through one or more refrigeration devices to provide cooling to the temperature-controlled objects stored or displayed therein. Such liquid coolant in such secondary cooling loops is typically circulated by a pump that draws coolant from a suction header and discharges the coolant to a discharge header. It would be desirable to provide a refrigeration system with a charging loop that is operable to maintain a pressure of the coolant in the suction header within a desired predetermined range. It would also be desirable to provide a charging loop that includes a minimum number of moving parts to simplify operation and maintenance of the system. It would be further desirable to provide a charging loop that provides make-up coolant to the suction header automatically upon a low-pressure condition. It would also be desirable to provide primary and back-up sources of make-up coolant to minimize the potential for introducing air into the secondary cooling system. Accordingly, it would be desirable to provide a refrigeration system having any one or more of these or other advantageous features.